1272165661 has 8 divisors (see below), whose sum is σ = 1370419064. Its totient is φ = 1173968640.

The previous prime is 1272165659. The next prime is 1272165679. The reversal of 1272165661 is 1665612721.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10850436 + 1261315225 = 3294^2 + 35515^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1272165661 - 2¹ = 1272165659 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1272165661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1272165061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40681 + ... + 64801.

It is an arithmetic number, because the mean of its divisors is an integer number (171302383).

Almost surely, 2^1272165661 is an apocalyptic number.

It is an amenable number.

1272165661 is a deficient number, since it is larger than the sum of its proper divisors (98253403).

1272165661 is a wasteful number, since it uses less digits than its factorization.

1272165661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28191.

The product of its digits is 30240, while the sum is 37.

The square root of 1272165661 is about 35667.4313765373. The cubic root of 1272165661 is about 1083.5473380982.

The spelling of 1272165661 in words is "one billion, two hundred seventy-two million, one hundred sixty-five thousand, six hundred sixty-one".